[compiler-rt] [compiler-rt] Fixed Android 8.1 `getauxval(AT_PAGESZ)` crashes if called from `.preinit_array`. (#113427) (PR #116121)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: None (funsafe-ptr)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/116121.diff


1 Files Affected:

- (modified) compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp (+13) 


``````````diff
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
index 04b095dca904ab..344b16be4a96e0 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
@@ -82,6 +82,12 @@
 #    include <sys/personality.h>
 #  endif
 
+# if SANITIZER_ANDROID && __ANDROID_API__ < 35
+// The weak strerrorname_np definition allows to check for the API level at
+// runtime.
+extern "C" SANITIZER_WEAK_ATTRIBUTE const char* strerrorname_np(int);
+# endif
+
 #  if SANITIZER_LINUX && defined(__loongarch__)
 #    include <sys/sysmacros.h>
 #  endif
@@ -1237,6 +1243,13 @@ uptr GetPageSize() {
   CHECK_EQ(rv, 0);
   return (uptr)pz;
 #    elif SANITIZER_USE_GETAUXVAL
+#      if SANITIZER_ANDROID && __ANDROID_API__ < 35
+  // The 16 KB page size was introduced in Android 15, while earlier versions 
+  // of Android used a 4 KB page size.
+  if (!strerrorname_np)
+    return 4096;
+#      endif
+
   return getauxval(AT_PAGESZ);
 #    else
   return sysconf(_SC_PAGESIZE);  // EXEC_PAGESIZE may not be trustworthy.

``````````

</details>


https://github.com/llvm/llvm-project/pull/116121